code: def test_native_query_show_dbs(self, handler):
      dbs = handler.native_query("SELECT datname FROM pg_database;")
      dbs = dbs.data_frame
      assert dbs is not None, "expected to get some data, but got None"
      assert (
          "datname" in dbs
      ), f"expected to get 'Database' column in response:\n{dbs}"
      dbs = list(dbs["datname"])
      expected_db = HANDLER_KWARGS["connection_data"]["database"]
      assert (
          expected_db in dbs
      ), f"expected to have {expected_db} db in response: {dbs}"
  
file_path: mindsdb/tests/handler_tests/test_postgres_handler.py
imports: import time
  import pytest
  import docker
  from mindsdb.integrations.handlers.postgres_handler.postgres_handler import PostgresHandler
  from mindsdb.api.executor.data_types.response_type import RESPONSE_TYPE
label_desc: Use image node_id 3 for calling the TestPostgresHandler obj's underlying member method code with example usage: obj.test_native_query_show_dbs(handler) without return types